According to the report, the stealing is usually done through inflating of procurement contract values and creating of "phantom" defence contracts.

"Such contracts are used as a vehicle for money laundering: facilitated via weak or corrupted Nigerian banks, illicit financial flows are often hidden in property in the UK, United States, South Africa and Dubai.

“The stealing is done with the active connivance of the country’s military leaders.

"With oil prices at a record low, defence has provided new and lucrative opportunities for the country’s corrupt kleptocrats.

“Former military chiefs have stolen as much as US $15 billion – a sum equivalent to half of Nigeria’s foreign currency reserves – through fraudulent arms procurement deals,” says the report.

Premium Times reports that the report was prepared in partnership with the Civil Society Legislative Advocacy Centre (CISLAC).

It is titled: 'Weaponising Transparency: Defence Procurement Reform As a Counterterrorism Strategy in Nigeria.'

The report acknowledged President Muhammadu Buhari administration’s effort to tackle corruption in the country’s defence sector., but warned that, “only a holistic reform agenda can deliver the deep, systemic changes and improvements in transparency and accountability needed to prevent the next US $15 billion quietly leaving Nigeria through the back door.

“President Buhari’s anti-corruption drive is a rare example of senior Nigerian defence and security officials being exposed to criminal investigation. By signalling that military impunity is not without limit, it is undoubtedly a positive step forward," it said.

President Buhari has cleansed the military of corrupt elements

The report recommends a unified anti-corruption strategy for the defence sector, the extension of public access to defence and security information, and the monitoring of confidential procurements as some of the ways of tackling the problem.

Other recommendations include the sharpening of international focus on fighting corruption in Nigeria, plucking off money laundering loopholes in banks, the extension of whistle-blower protection to cover the defence sector, and regulation of secretive security votes.